import sys
input=sys.stdin.readline

class list2D:
    def __init__(self, H, W, num):
        self.__H = H
        self.__W = W
        self.__dat = [num] * (H * W)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__W+a[1]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__W+a[1]] = b

    def debug(self):
        print(self.__dat)

class list3D:
    def __init__(self, H, W, D, num):
        self.__H = H
        self.__W = W
        self.__D = D
        self.__X = W * D
        self.__dat = [num] * (H * W * D)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b

    def debug(self):
        print(self.__dat)

def main():
    r,c,k=map(int,input().split())
    v = list2D(r, c, 0)

    for _ in range(k):
        ri,ci,a=map(int,input().split())
        v[ri-1, ci-1] = a

    dp = list3D(r, c, 4, 0)
    #print(dp)
    if v[0, 0]>0: dp[0, 0, 1]=v[0, 0]

    for i in range(r):
        for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
    ans=0
    for i in range(4): ans=max(dp[r-1, c-1, i],ans)
    return print(ans)
if __name__=="__main__":
    main() import sys sys input=sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline class list2D:
    def __init__(self, H, W, num):
        self.__H = H
        self.__W = W
        self.__dat = [num] * (H * W)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__W+a[1]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__W+a[1]] = b

    def debug(self):
        print(self.__dat) list2D def __init__(self, H, W, num):
        self.__H = H
        self.__W = W
        self.__dat = [num] * (H * W)

     __init__ self.__H = H self.__H self __H H self.__W = W self.__W self __W W self.__dat = [num] * (H * W) self.__dat self __dat [num] * (H * W) [num] num H * W H W self self H H W W num num def __getitem__(self, a):
        return self.__dat[a[0]*self.__W+a[1]]

     __getitem__ return self.__dat[a[0]*self.__W+a[1]] self.__dat[a[0]*self.__W+a[1]] self.__dat self __dat a[0]*self.__W+a[1] a[0]*self.__W a[0] a 0 self.__W self __W a[1] a 1 self self a a def __setitem__(self, a, b):
        self.__dat[a[0]*self.__W+a[1]] = b

     __setitem__ self.__dat[a[0]*self.__W+a[1]] = b self.__dat[a[0]*self.__W+a[1]] self.__dat self __dat a[0]*self.__W+a[1] a[0]*self.__W a[0] a 0 self.__W self __W a[1] a 1 b self self a a b b def debug(self):
        print(self.__dat) debug print(self.__dat) print self.__dat self __dat self self class list3D:
    def __init__(self, H, W, D, num):
        self.__H = H
        self.__W = W
        self.__D = D
        self.__X = W * D
        self.__dat = [num] * (H * W * D)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b

    def debug(self):
        print(self.__dat) list3D def __init__(self, H, W, D, num):
        self.__H = H
        self.__W = W
        self.__D = D
        self.__X = W * D
        self.__dat = [num] * (H * W * D)

     __init__ self.__H = H self.__H self __H H self.__W = W self.__W self __W W self.__D = D self.__D self __D D self.__X = W * D self.__X self __X W * D W D self.__dat = [num] * (H * W * D) self.__dat self __dat [num] * (H * W * D) [num] num H * W * D H * W H W D self self H H W W D D num num def __getitem__(self, a):
        return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]]

     __getitem__ return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] self.__dat self __dat a[0]*self.__X+a[1]*self.__D + a[2] a[0]*self.__X+a[1]*self.__D a[0]*self.__X a[0] a 0 self.__X self __X a[1]*self.__D a[1] a 1 self.__D self __D a[2] a 2 self self a a def __setitem__(self, a, b):
        self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b

     __setitem__ self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] self.__dat self __dat a[0]*self.__X+a[1]*self.__D + a[2] a[0]*self.__X+a[1]*self.__D a[0]*self.__X a[0] a 0 self.__X self __X a[1]*self.__D a[1] a 1 self.__D self __D a[2] a 2 b self self a a b b def debug(self):
        print(self.__dat) debug print(self.__dat) print self.__dat self __dat self self def main():
    r,c,k=map(int,input().split())
    v = list2D(r, c, 0)

    for _ in range(k):
        ri,ci,a=map(int,input().split())
        v[ri-1, ci-1] = a

    dp = list3D(r, c, 4, 0)
    #print(dp)
    if v[0, 0]>0: dp[0, 0, 1]=v[0, 0]

    for i in range(r):
        for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
    ans=0
    for i in range(4): ans=max(dp[r-1, c-1, i],ans)
    return print(ans) main r,c,k=map(int,input().split()) r map(int,input().split()) map int input().split() ().split () input split c k v = list2D(r, c, 0) v list2D(r, c, 0) list2D r c 0 for _ in range(k):
        ri,ci,a=map(int,input().split())
        v[ri-1, ci-1] = a

     _ range(k) range k ri,ci,a=map(int,input().split()) ri map(int,input().split()) map int input().split() ().split () input split ci a v[ri-1, ci-1] = a v[ri-1, ci-1] v ri-1 ri 1 a dp = list3D(r, c, 4, 0) dp list3D(r, c, 4, 0) list3D r c 4 0 if v[0, 0]>0: dp[0, 0, 1]=v[0, 0]

     v[0, 0]>0 v[0, 0] v 0 0 for i in range(r):
        for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
     i range(r) range r for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
     j range(c) range c val = v[i, j] val v[i, j] v i if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

             i>0 i 0 x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3]) x max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3]) max dp[i-1, j, 0] dp i-1 i 1 dp[i-1, j, 1] dp i-1 i 1 dp[i-1, j, 2] dp i-1 i 1 dp[i-1, j, 3] dp i-1 i 1 dp[i, j, 1]=max(dp[i, j, 1],x+val) dp[i, j, 1] dp i max(dp[i, j, 1],x+val) max dp[i, j, 1] dp i x+val x val dp[i, j, 0]=max(dp[i, j, 0],x) dp[i, j, 0] dp i max(dp[i, j, 0],x) max dp[i, j, 0] dp i x if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
     j>0 j 0 X = dp[i, j-1, 0] X dp[i, j-1, 0] dp i Y = dp[i, j-1, 1] Y dp[i, j-1, 1] dp i V = dp[i, j-1, 2] V dp[i, j-1, 2] dp i Z = dp[i, j-1, 3] Z dp[i, j-1, 3] dp i dp[i, j, 0]=max(dp[i, j, 0],X) dp[i, j, 0] dp i max(dp[i, j, 0],X) max dp[i, j, 0] dp i X dp[i, j, 1]=max(dp[i, j, 1],X+val,Y) dp[i, j, 1] dp i max(dp[i, j, 1],X+val,Y) max dp[i, j, 1] dp i X+val X val Y dp[i, j, 2]=max(dp[i, j, 2],Y+val,V) dp[i, j, 2] dp i max(dp[i, j, 2],Y+val,V) max dp[i, j, 2] dp i Y+val Y val V dp[i, j, 3]=max(dp[i, j, 3],V+val,Z) dp[i, j, 3] dp i max(dp[i, j, 3],V+val,Z) max dp[i, j, 3] dp i V+val V val Z ans=0 ans 0 for i in range(4): ans=max(dp[r-1, c-1, i],ans)
     i range(4) range 4 return print(ans) print(ans) print ans if __name__=="__main__":
    main() __name__=="__main__" __name__ "__main__" main() main input=sys.stdin.readline sys.stdin.readline input class list3D:
    def __init__(self, H, W, D, num):
        self.__H = H
        self.__W = W
        self.__D = D
        self.__X = W * D
        self.__dat = [num] * (H * W * D)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b

    def debug(self):
        print(self.__dat) class list3D:
    def __init__(self, H, W, D, num):
        self.__H = H
        self.__W = W
        self.__D = D
        self.__X = W * D
        self.__dat = [num] * (H * W * D)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b

    def debug(self):
        print(self.__dat) list3D class list2D:
    def __init__(self, H, W, num):
        self.__H = H
        self.__W = W
        self.__dat = [num] * (H * W)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__W+a[1]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__W+a[1]] = b

    def debug(self):
        print(self.__dat) class list2D:
    def __init__(self, H, W, num):
        self.__H = H
        self.__W = W
        self.__dat = [num] * (H * W)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__W+a[1]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__W+a[1]] = b

    def debug(self):
        print(self.__dat) list2D def main():
    r,c,k=map(int,input().split())
    v = list2D(r, c, 0)

    for _ in range(k):
        ri,ci,a=map(int,input().split())
        v[ri-1, ci-1] = a

    dp = list3D(r, c, 4, 0)
    #print(dp)
    if v[0, 0]>0: dp[0, 0, 1]=v[0, 0]

    for i in range(r):
        for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
    ans=0
    for i in range(4): ans=max(dp[r-1, c-1, i],ans)
    return print(ans) def main():
    r,c,k=map(int,input().split())
    v = list2D(r, c, 0)

    for _ in range(k):
        ri,ci,a=map(int,input().split())
        v[ri-1, ci-1] = a

    dp = list3D(r, c, 4, 0)
    #print(dp)
    if v[0, 0]>0: dp[0, 0, 1]=v[0, 0]

    for i in range(r):
        for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
    ans=0
    for i in range(4): ans=max(dp[r-1, c-1, i],ans)
    return print(ans) main
import sys
input=sys.stdin.readline

class list2D:
    def __init__(self, H, W, num):
        self.__H = H
        self.__W = W
        self.__dat = [num] * (H * W)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__W+a[1]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__W+a[1]] = b

    def debug(self):
        print(self.__dat)

class list3D:
    def __init__(self, H, W, D, num):
        self.__H = H
        self.__W = W
        self.__D = D
        self.__X = W * D
        self.__dat = [num] * (H * W * D)

    def __getitem__(self, a):
        return self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]]

    def __setitem__(self, a, b):
        self.__dat[a[0]*self.__X+a[1]*self.__D + a[2]] = b

    def debug(self):
        print(self.__dat)

def main():
    r,c,k=map(int,input().split())
    v = list2D(r, c, 0)

    for _ in range(k):
        ri,ci,a=map(int,input().split())
        v[ri-1, ci-1] = a

    dp = list3D(r, c, 4, 0)
    #print(dp)
    if v[0, 0]>0: dp[0, 0, 1]=v[0, 0]

    for i in range(r):
        for j in range(c):
            val = v[i, j]
            if i>0:
                x = max(dp[i-1, j, 0], dp[i-1, j, 1], dp[i-1, j, 2], dp[i-1, j, 3])
                dp[i, j, 1]=max(dp[i, j, 1],x+val)
                dp[i, j, 0]=max(dp[i, j, 0],x)

            if j>0:
                X = dp[i, j-1, 0]
                Y = dp[i, j-1, 1]
                V = dp[i, j-1, 2]
                Z = dp[i, j-1, 3]
                dp[i, j, 0]=max(dp[i, j, 0],X)
                dp[i, j, 1]=max(dp[i, j, 1],X+val,Y)
                dp[i, j, 2]=max(dp[i, j, 2],Y+val,V)
                dp[i, j, 3]=max(dp[i, j, 3],V+val,Z)

    #print(dp)
    ans=0
    for i in range(4): ans=max(dp[r-1, c-1, i],ans)
    return print(ans)
if __name__=="__main__":
    main()
